A vote to ratify the UN Convention on the Rights of Persons With Disabilities fell short in the Senate, with the measure getting six votes less than the 67 needed for ratification. Thirty-eight Republicans voted no. Eight Republicans voted in favor of the treaty.

While most Republican lawmakers felt the treaty threatened U.S. sovereignty, most Democrats said the treaty would promote equal rights for disabled people around the world, including those with physical disabilities such as blindness.

If the Senate had voted for ratification, the United States would have joined 126 other countries. The treaty was modeled on American legislation, the 1990 Americans with Disabilities Act.

The U.N. Convention on the Rights of Persons With Disabilities established a committee to recommend actions to governments - such as building wheelchair ramps or taking steps to make it easier for disabled children to attend school - though it cannot require specific actions. President Obama signed the convention, which was negotiated during George W. Bush's administration, in 2009. More than one billion people - roughly 15 percent of the world's population - live with a disability, according to the World Health Organization.

Conservatives, including former Republican presidential candidate Rick Santorum, had opposed the treaty saying it threatened U.S. sovereignty and parental rights.

Sen. Santorum, who has a daughter with special needs, had argued that the treaty would effectively put the United States under international law and give the U.N. discretion over decisions about how special needs children are educated.

The eight Republicans in favor of the treaty included Vietnam War veteran Sen. John McCain.